popen

(PHP 4, PHP 5, PHP 7)

Opens process file pointer

resource popen ( string $command, string $mode )

Opens a pipe to a process executed by forking the command given by command.

Parameters:

command

The command

mode

The mode

Returns:

Returns a file pointer identical to that returned by fopen(), except that it is unidirectional (may only be used for reading or writing) and must be closed with pclose(). This pointer may be used with fgets(), fgetss(), and fwrite(). When the mode is 'r', the returned file pointer equals to the STDOUT of the command, when the mode is 'w', the returned file pointer equals to the STDIN of the command.

If an error occurs, returns FALSE.

Notes:

If you're looking for bi-directional support (two-way), use proc_open().

When safe mode is enabled, you can only execute files within the safe_mode_exec_dir. For practical reasons, it is currently not allowed to have .. components in the path to the executable.

Examples:

popen() example

<?php
$handle = popen("/bin/ls", "r");
?>

popen() example

If the command to be executed could not be found, a valid resource is returned. This may seem odd, but makes sense; it allows you to access any error message returned by the shell:

<?php
error_reporting(E_ALL);

/* Add redirection so we can get stderr. */
$handle = popen('/path/to/executable 2>&1', 'r');
echo "'$handle'; " . gettype($handle) . "\n";
$read = fread($handle, 2096);
echo $read;
pclose($handle);
?>